La percepción de etileno a través de ETR3 determina la interacción de las plantas con bacterias promotoras del crecimiento vegetal en tomate (Solanum lycopersicum)

Este trabajo ha sido financiado mediante la beca de Formación de Personal Investigador (Ref. ayuda FPI: BES-2012-058155) concedida por el Ministerio de Economía y Competitividad (Ref. Proyecto AGL2011-25403).La presente Tesis Doctoral persigue principalmente arrojar luz sobre la interacción entre dos bacterias promotoras del crecimiento vegetal y plantas de tomate en relación con la sensibilidad a etileno mediante el uso de diferentes metodologías con el objetivo de elucidar los mecanismos de acción bacteriana. En consecuencia, el mutante insensible a etileno never ripe (nr) (incapaz de percibir etileno debido a una mutación en el receptor de etileno SlETR3) (Lanahan et al. 1994; Wilkinson et al. 1995), y su parental isogénico de tipo silvestre (wild-type; wt) de tomate (Solanum lycopersicum) cultivar Pearson fueron seleccionados para ser inoculados con cepas PGPB aisladas de suelos áridos de la zona sur de España: Bacillus megaterium (Bm) (Marulanda-Aguirre et al. 2008) y Enterobacter sp. (en adelante Enterobacter C7 (C7)). Debido a que la mayoría de los estudios sobre el papel del etileno en la actividad PGPB se han centrado en bacterias que son capaces de reducir los niveles de ACC (Glick 2014), este estudio pretende utilizar bacterias sin actividad ACC deaminasa o la capacidad de producir etileno para evitar cualquier perturbación directa del metabolismo del etileno de la planta.Tesis Univ. Granada. Programa Oficial de Doctorado en: Biología Fundamental y de Sistema

Turnip Mosaic Virus Coat Protein Deletion Mutants Allow Defining Dispensable Protein Domains for ‘in Planta’ eVLP Formation

The involvement of different structural domains of the coat protein (CP) of turnip mosaic virus, a potyvirus, in establishing and/or maintaining particle assembly was analyzed through deletion mutants of the protein. In order to identify exclusively those domains involved in protein–protein interactions within the particle, the analysis was performed by agroinfiltration “in planta”, followed by the assessment of CP accumulation in leaves and the assembly of virus-like particles lacking nucleic acids, also known as empty virus-like particles (eVLP). Thus, the interactions involving viral RNA could be excluded. It was found that deletions precluding eVLP assembly did not allow for protein accumulation either, probably indicating that non-assembled CP protein was degraded in the plant leaves. Deletions involving the CP structural core were incompatible with particle assembly. On the N-terminal domain, only the deletion avoiding the subdomain involved in interactions with other CP subunits was incorporated into eVLPs. The C-terminal domain was shown to be more permissive to deletions. Assembled eVLPs were found for mutants, eliminating the whole domain. The C-terminal domain mutants were unusually long, suggesting some role of the domain in the regulation of particle length. The identification of the CP domains responsible for eVLP formation will allow for new approaches to protein stretch replacement with peptides or proteins of nanobiotechnological interest. Finally, specific cases of application are considered

Proteomic analysis reveals that tomato interaction with plant growth promoting bacteria is highly determined by ethylene perception

Feeding an increasing global population as well as reducing environmental impact of crops is the challenge for the sustainable intensification of agriculture. Plant-growth-promoting bacteria (PGPB) management could represent a suitable method but elucidation of their action mechanisms is essential for a proper and effective utilization. Furthermore, ethylene is involved in growth and response to environmental stimuli but little is known about the implication of ethylene perception in PGPB activity. The ethylene-insensitive tomato never ripe and its isogenic wild-type cv. Pearson lines inoculated with Bacillus megaterium or Enterobacter sp. C7 strains were grown until mature stage to analyze growth promotion, and bacterial inoculation effects on root proteomic profiles. Enterobacter C7 promoted growth in both plant genotypes, meanwhile Bacillus megaterium PGPB activity was only noticed in wt plants. Moreover, PGPB inoculation affected proteomic profile in a strain- and genotype-dependent manner modifying levels of stress-related and interaction proteins, and showing bacterial inoculation effects on antioxidant content and phosphorus acquisition capacity. Ethylene perception is essential for properly recognition of Bacillus megaterium and growth promotion mediated in part by increased levels of reduced glutathione. In contrast, Enterobacter C7 inoculation improves phosphorus nutrition keeping plants on growth independently of ethylene sensitivity.This work was supported by Spanish Ministry of Economy and Competitiveness (BES-2012-058155)Peer Reviewe

On the Representation of Orthogonally Additive Polynomials in l(p)

We present a new proof of a Sundaresan's result which shows that the space of orthogonally additive polynomials P-0((k)l(p)) is isometrically isomorphic to l(p/p-k) if k < p < infinity and to l(infinity) if 1 <= p <= k

On the multilinear trigonometric problem of moments

A multilinear generalization of the trigonometric problem of moments is presented and discussed. The moments c(k), k is an element of Z(n) of a regular Borel polymeasure gamma on T(n) are characterized by means of a norm parallel to . parallel to(omega) on functions on Z(n). Some properties of this norm are analyzed and various examples are presented showing that it is strictly weaker than the Frechet norms and the absolute convergence norm. The convolution product of multilinear functionals is defined and an inverse theorem is proved

Turnip Mosaic Virus Coat Protein Deletion Mutants Allow Defining Dispensable Protein Domains for 'in Planta' eVLP Formation

10 Pág.The involvement of different structural domains of the coat protein (CP) of turnip mosaic virus, a potyvirus, in establishing and/or maintaining particle assembly was analyzed through deletion mutants of the protein. In order to identify exclusively those domains involved in protein-protein interactions within the particle, the analysis was performed by agroinfiltration "in planta", followed by the assessment of CP accumulation in leaves and the assembly of virus-like particles lacking nucleic acids, also known as empty virus-like particles (eVLP). Thus, the interactions involving viral RNA could be excluded. It was found that deletions precluding eVLP assembly did not allow for protein accumulation either, probably indicating that non-assembled CP protein was degraded in the plant leaves. Deletions involving the CP structural core were incompatible with particle assembly. On the N-terminal domain, only the deletion avoiding the subdomain involved in interactions with other CP subunits was incorporated into eVLPs. The C-terminal domain was shown to be more permissive to deletions. Assembled eVLPs were found for mutants, eliminating the whole domain. The C-terminal domain mutants were unusually long, suggesting some role of the domain in the regulation of particle length. The identification of the CP domains responsible for eVLP formation will allow for new approaches to protein stretch replacement with peptides or proteins of nanobiotechnological interest. Finally, specific cases of application are considered.This work was financially supported by grants RTA2015-00017 (INIA funding agent), APCIN2016-00014-00-00 (INIA funding through the Era-Net project NANOBIOAGRI, of the ARIMNet-2 program), and FoodAl (S2018/BAA-4574, Autonomous Region of Madrid funding), which also provided the postdoctoral contract for CY-C.Peer reviewe

Molecular insights into the involvement of a never ripe receptor in the interaction between two beneficial soil bacteria and tomato plants under well-Watered and drought conditions

Management of plant growth–promoting bacteria (PGPB) can be implemented to deal with sustainable intensification of agriculture. Ethylene is an essential component for plant growth and development and in response to drought. However, little is known about the effects of bacterial inoculation on ethylene transduction pathway. Thus, the present study sought to establish whether ethylene perception is critical for growth induction by two different PGPB strains under drought conditions and the analysis of bacterial effects on ethylene production and gene expression in tomatoes (Solanum lycopersicum). The ethylene-insensitive never ripe (nr) and its isogenic wild-type (wt) cv. Pearson line were inoculated with either Bacillus megaterium or Enterobacter sp. strain C7 and grown until the attainment of maturity under both well-watered and drought conditions. Ethylene perception is crucial for B. megaterium. However, it is not of prime importance for Enterobacter sp. strain C7 PGPB activity under drought conditions. Both PGPB decreased the expression of ethylene-related genes in wt plants, resulting in stress alleviation, while only B. megaterium induced their expression in nr plants. Furthermore, PGPB inoculation affected transcriptomic profile dependency on strain, genotype, and drought. Ethylene sensitivity determines plant interaction with PGPB strains. Enterobacter sp. strain C7 could modulate amino-acid metabolism, while nr mutation causes a partially functional interaction with B. megaterium, resulting in higher oxidative stress and loss of PGPB activity.This work was performed under framework of project AGL2011-25403. P. Ibort was financed by Spanish Ministry of Economy and Competitive BES-2012-058155Peer Reviewe

Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants

The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp(o)) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp(o) in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp(o) only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp(o) is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp(o) to environmental changes

Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants

Main conclusion: The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp to environmental changes.This work was supported by the Ministry of Economy and Competitiveness of Spain (Juan de la Cierva Program and AGL2011-25403 project) and Junta de Andalucía (P10-CVI-5920 project)Peer Reviewe